Current control for generators



March 17, 1942. R. G. LAI-'ITE CURRENT CONTROL FOR GENERATORS Filed July 13, 19:59

VS1 @IL INVENTOR, qye/{ af/7e BY s Z' ATTORNEYS Patentecl Mar. 17, 1942 UNITED STATES PATENT OFFICE CURRENT CONTROL FOR GENERATORS Roger G. Lafite, Kansas City, Mo.

Application July 13, 1939, Serial No. 284,235

1 Claim.

This invention relates to generator controlling devices and has for its primary object, the provision of such a device mounted on a base and covered with a case sealed thereto; the said controlling device including a current limiting relay which may be adjusted to operate at various current values, said adjustment being made from a point exterior to the case, and while the said case is sealed to the base; the feature of the said exterior adjustment being for the purpose of permitting said device to be selectively set for the particular current value desired, without breaking the said seal to gain access to interior adjustment means.

The advantage of said exterior adjustment will be understood when it is realized that when such generator controlling devices are sold as replacements of original controlling devices, as on automobiles, they may be purchased for installation on generators of different current values, and therefore, it is important to provide a means of quickly adjusting them for the proper current required for the particular generator with which they are intended to be used, without breaking the seal holding the cover to the base, which otherwise would void the manufacturers guarantee.

The manner in which my invention accomplishes the said selective adjustment of current values, is to alter the length of the air gap between the armature and the top of the core, to cause the contacts to open at a lower current value when said air gap is small, and at a greater Value when the air gap is larger, thus obtaining a range of operative current values determined by the length of said air gap; and making such adjustments from a point outside the controlling device when its base is sealed to the cover.

A further object of this invention is to provide a means for indicating to the person making the above adjustment, the correct position at which any such adjustment can be made; said means including a longitudinally adjustable core, an indicator, and a scale, together with means for selectively locking the core in any one of a number of positions, said positions being indicated by marks on said scale corresponding to the ampere output for which the said adjustment is to be made.

Further objects of the invention will appear during the course of the following specification, referring to the accompanying drawing, wherein:

Figure 1 is a top plan view of a generator controlling device for generators, embodying a reverse current relay, a voltage regulator, and a current limiting relay made in accordance with this invention.

Fig. 2 is a side elevational view of the generator controlling device, a part of the cover being broken away for clearness.

Fig. 3 is a vertical cross sectional View through the current limiting relay, taken on line III-III of Fig. 2.

Fig. 4 is an enlarged fragmentary inverted plan view of a portion of the current limiting relay assembly; and

Fig. 5 is an enlarged detailed fragmentary sectional view taken on line V--V of Fig. 3.

It is a matter of great convenience to the merchandiser of automotive parts to stock a generator `controlling device assembly that can be selectively adjusted before delivery to the pur- Chaser, Where the latter may install the same to secure the proper results for his particular generator.

Obviously, if such a controlling device is adjusted for a current value too large or too small for the generator in connection with which it is to be used, undesirable results will follow; if the adjustment made is for a current smaller than the capacity of his generator, the purchaser will not obtain the current capacity required for his needs; and if the said controlling device is adjusted for a current higher than the safe output of his generator, said generator will soon be subjected to destructive forces.

Over a period of years, automobiles have been constructed having generators of different current capacities, and the manufacturer of replacement generator controlling devices has had difficulty in providing such devices adjusted for the various current requirements, because of the prohibitively large stock that the distributor of said devices must carry, if the demands of the p urchasing public is to be properly met. Therefore, it is desirable, and an important object of this invention, to provide a current limiting relay in a generator controlling device, that may be quickly and accurately adjusted for use with any one of a number of generators of different rated maximum outputs, without voiding the manufacturers guarantee which is contingent upon not breaking the seal holding the cover of such controlling device to its base.

The conventional voltage and current generator controlling device includes a current limiting relay which comprises a base 8 over which is secured a cover I0 through the medium of screws or the like I2, one of which is provided with a seal I4. If this seal is broken, the manufacturers guarantee no longer prevails and therefore, some semblance of insurance is possessed by the manufacturer and distributor of the assembly.

A voltage regulator I6 is mounted on base 8 within cover I6 as is the reverse current relay I8. These units comprise no part of this invention.

The current limiting relay 20 is housed within cover I6 with units I6 and i8. Current limiting relay 26 comprises an armature 22 movable to and from a position where points 24 and 26 meet, so as to close the circuit from the generator eld to the proper generator brush. When the generator current exceeds the value for which the relay is set, armature 22 is attracted towards core 48 of the relay, thus causing points 24 and 26 to separate, to force the field current to be diverted through a resistance unit, not here shown, which temporarily decreases the generator Voltage, and prevents the generator current from reaching a value higher than that for which the current limiting relay is set.

A coil 28, in series with the generator output circuit actuates the current limiting relay and the specially constructed core comprises a tubular member 36 which circumscribes a longitudinally movable element 32. Tubular member 3D is fixed in place and mounted directly on base 8 so that it cannot move when element 32 is turned.

A reduced, exteriorly threaded portion 34 on element 32 is in screw-threaded engagement with internally threaded reduced neck 36 of member 30. Member 38 extends below base 8 and is exteriorly threaded along the portion which projects outwardly.

A nut 33 provided with a number of radial notches 46 is mounted upon member 30 immediately over a scale 4l, upon which indicia 42 .are

printed or otherwise marked.

In the instance illustrated, there are eight stations marked on scale 4|, and the indicia 42 indicate the ampere output ofthe generator.

A cotter key or cross pin 4:4 extends through a transverse opening formed in yelement 32, which opening is in alignment with kerf 46 milled in Athe end of element 32.

Pin 44 becomes a lock as welllas a pointer, and in the instance shown, the current limiting relay is set for use with a generator having the rated output of thirty-two amperes. Obviously, when it is desired to alter the adjustment of the current limiting relay to control a generator of a safe maximum output of 20, 22, 24, 26, 28 or 30 .e1'ators, a base;

amperes, pin 44 is rst removed, and element 32 is turned to a position where kerf 46 is in alignment with the notch in nut 38 corresponding to the rating shown on scale 4l for which it is desired to set the current limiting relay. Pin 44 is then replaced to secure the parts against accidental displacement.

Scale 4| is rigidly secured against movement to the bottom of base 8, and nut 38 is similarly attached to the scale.

Obviously, when element 32 is rotated clockwise, when viewed from the bottom, its upper end will move toward armature 22 to establish an air `gap of suitable size and thereby cause said armature to open contacts 24 and 26 when a current of a predetermined size corresponding to the selected air gap is passing through the coil 28,

Generator controlling devices having physical characteristics other than those shown in the drawing and described in the foregoing specication, might be constructed without departing from the .spirit of the invention or scope of the appended claim.

Having thus described the invention, what is claimed as new and .desired to-be secured -by Letters Patent is:

In a current regulator for automobile gena current limiting relay supported -on and above the base; a cover for the relay mounted .on the base; iianges depending from the base `and yforming an enclosure below the base and serving as a means to support the base; said relay comprising a sleeve; a current coil surrounding said sleeve; one end of the sleeve being threaded and extending through the base within said enclosure; -a lnut threadedly engaging said threaded sleeve-end and serving to retain the sleeve and .coil on said base; an ad- Justable core within said sleeve; a reduced threaded portion fof predetermined length on the core at .one end thereof; an internally threaded reduced neck of predetermined `length at the other end of the sleeve -to cooperate with the threads on the core; an armature positioned adjacent the one end of said core; the other endof the core extending through and beyond the nut; indicia at said other end of the core for indicating the relative position of the core with respect to the armature; and means adjacent said other end for vlocking the core in `selected position after rotation Athereof -to provide desired adjustment.

ROGER G. LAFITE. 

